fix: remove hardcoded localhost default arg from GET /api/keys, unify coverage to single coverage/ dir, fix test to pass explicit Request

- Remove `new Request('http://localhost/api/keys')` default arg from GET handler in src/app/api/keys/route.ts (line 26)
- Fix api-key-reveal-route.test.mjs to pass explicit Request instead of calling GET() with no args
- Add --output-dir coverage to all c8 scripts in package.json
- Add coverage.reportsDirectory: 'coverage' to vitest.config.ts and vitest.mcp.config.ts
- Fix CHANGELOG.md structure (# Changelog + [Unreleased] to top)
- Remove 30+ stale coverage-* directories from project root
- Coverage: Statements 78.76% | Branches 72.75% | Functions 80.93% | Lines 78.76% (all thresholds passed)

tsconfig.json

@@ -35,7 +35,9 @@
     "**/*.jsx",
     ".next/types/**/*.ts",
     ".next/dev/types/**/*.ts",
-    ".next/dev/dev/types/**/*.ts"
+    ".next/dev/dev/types/**/*.ts",
+    ".next-playwright/types/**/*.ts",
+    ".next-playwright/dev/types/**/*.ts"
   ],
   "exclude": [
     "node_modules",